Of course this kind of stuff happens. Speaking from experience, war is an intrinsically dehumanizing thing. That is a significant aspect of its nature. What’s different now, as with all of our quasi-imperial entanglements, is that the public has no significant investment in the cause.
In WWII, body part trophies and desecration were common knowledge; there are plenty of photographs and records of it. It’s just that the public was totally mobilized and had a whole-hearted embrace of the cause. Our wars now are sideshows in which the majority of the public has no investment. It’s not that things like this are surprising; they just remind people without an investment in it that war is icky (not an infantryman’s description, to be sure).
But there’s also no way to stop that type of reaction, no matter how much we may want to complain about it. It’s an inevitable consequence of engaging in faraway wars that degenerate into the equivalent of bloody police actions. The right answer for policymakers is to finally get it through their enormously thick skulls that public support for these types of wars always diminishes with time. The public will always turn on these types of wars as they linger on and on.
There’s only so much you can do with someone else’s country. Figure out what that is, be ruthlessly realistic to yourself about it, and figure out one or two very specific, achievable things you intend to accomplish. Do that and leave. And if you can’t think of one or two very specific, achievable things, that’s reality telling you to not get involved in the first place.